Abstract: The study investigated the zooplankton community composition and environmental factors in polyculture pond with high density of bighead carp (Aristichthys nobilis), yellow catfish (Pelteobagrus fulvidraco) and silver carp (Hypophthalmichthys molitrix.) The ponds were treated with 1/4 block (group A), 1/2 block (group B) and no block (group C) meshes to investigate whether the blocking regulate the survival pressure of zooplankton population. The results showed that TSS decreased significantly (P<0.05) in groups A and B, while nutrients as TN and TP significantly increased (P<0.05) in these two groups. The species of protozoa and rotifers in all groups were relatively high, accounting for 30.4%—36.6% and 51.6%—57.0%, respectively, while species of cladocera and copepods were relatively lower. There was no significant difference in species composition of each group, and species diversity (H') in groups A and B were significantly higher at two sampling times (July 9^th and July 23^rd) than that in group C. In addition, the dominant populations in all groups were protozoa and rotifers, but rotifers tended to decrease in later time point. Moreover, the dominant species Moina macrocopa disappeared in group C overtime, while it still presented in group A and B. There were no significant difference in the biomass of rotifers and protozoa in each group during the experiment, while the total biomass of cladocera and copepods was significantly higher in group B than those in groups A and C, indicating that blocking culture could reduce the survival pressure of large zooplankton population and slow down the decline of biomass. These results would provide a positive guide in maintaining ecological balance and increase nature food of bighead carp in the high diversity culture pond.